Disclosed herein is a heat dissipating system, specifically, a heat dissipating system for a light source, and more specifically, a heat dissipating system for a light emitting diode (LED) module of a vehicle.
Light emitting diodes (LEDs) are currently used as replacements for incandescent light bulbs and fluorescent lamps. LEDs are semiconductor devices that emit incoherent narrow-spectrum light when electrically biased in the forward direction of their PN junctions, and are thus referred to as solid-state lighting devices. The high power LED light devices produce considerable amount of heat, which may cause performance degradation or even damage if the heat is not removed from the LED chips efficiently.
In an LED light device, the core is a LED chip mounted on a substrate. Sometimes a transparent covering over the LED chip can serve as a lens for modifying the direction of the emitted light.
In general, LED chips in an automotive headlamp need to be maintained below certain temperatures as an increased temperature of the chip can reduce the life of the LED exponentially, and can adversely affect the light output of the LED light device. Maintaining such a reduced temperature is a challenge, as a significant amount of heat from the engine compartment is generated during vehicle operation in addition to the heat produced by the LED lighting device itself. Typically, cooling of a LED chip is achieved by using a large aluminum die cast heat sink system on the LED assembly. However, conventional heat sink systems can occupy a significant amount of space inside the headlamp assembly and thus add excessive weight to the headlamp assembly.
Moreover, in automotive headlamps, the beam patterns may need to be adjusted depending upon the requirements of the automotive vehicle. These adjustments, also referred to as “auto leveling” of the headlamp is typically performed with the use of a small electric motor. In adaptive lighting, the beam can be adjusted continuously based on the speed of the vehicle and also based on the steering position. In such cases, if the headlamp assembly is heavy, the response time could be high or heavier motors may need to be employed to affect the proper adjustments. Actually, as much as 400 grams (g) of die cast heat sink is being used in some vehicle headlamps.
Thus, there is a continual need for LED headlamp assemblies having reduced weight, as well as effective methods of dissipating heat away from a LED chip of a LED assembly that could enable the use of smaller, lighter weight components and/or the elimination of some thermally conductive components in the headlamp assembly.